Weirdly, I think the only thing that was really bothering me about the logo is that it just looked like all the pieces had been brought together and then stacked. If you move the volcano to the side, I think it looks slightly better but at the end of the day, it doesn't really matter.
I did mess around with some other colours but given it's a water park, you can't really use anything but, purples, blues and greens and that's why a lot of water parks look kind of similar. Every logo will have some kind of water in it some where, which puts yellow out the question because who wants to go into yellow water? The same idea can be used for orange and red.